Electrical connector



March 16, 1965 R. G. HARTWELL 3,173,734

ELECTRICAL CONNECTOR Filed June 18, 1962 a Sheets-Sheet 1 March 16, 1965 e. HARTWELL 3,173,734

ELECTRICAL CONNECTOR Filed June 18, 1962 6 Sheets-Sheet 2 QM Hlllllllll llli llll ll us as" 6 Lkr/ 5 I e 55 Hi H mm f? 62 la M 56 as F'ETE R. e. HARTWELL ELECTRICAL CONNECTOR March 16, 1965 Filed June 18, 1962 a Sheets-Sheet 3 March 16, 1965 R. G. HARTWELL 3,173,734

ELECTRICAL CONNECTOR Filed June 18, 1962 '6 Sheets-Sheet 4 w 3a 4a 3e March 16, 1965 R. G. HARTWELL 3,173,734

ELECTRICAL CONNECTOR Filed June 18, 1962 6 Sheets-Sheet 5 6 Sheets-Sheet 6 Filed June 18, 1962 United States Patent 3,173,734 ELEII'IRICAL (IGNNEQTOR Ronald G. Hartwell, Hummelstewn, Pa, assignor to AMP Incorporated, Harrisburg, Pa. Filed June 18, I962, Ser. No. 293,353 6 tllaims. (Cl. 33949) This invention relates to multi-contact electrical connecting devices for making disengageable electrical connections among a plurality of wires or other conductors.

A conventional multi-contact connecting device comprises a pair of matable insulating blocks each having a plurality of electrical contacts therein which are secured to the ends of wires so that when the blocks are brought into engagement with each other, the contacts are also engaged with each other and the wires are electrically connected. The insulating blocks are herein referred to as connectors and a pair of mated connectors are referred to as a connector assembly.

Connectors of the above described general type are available in different sizes for disengageably connecting different numbers of conductors. The largest commonly used connectors contain about 100 contact terminals although connectors providing accommodation for even higher numbers of contacts are available. A comparative disadvantage of multi-contact connecting devices is that a large variety of connectors of all sizes must be kept on hand by the user if he wishes to make connections for varying numbers of conductors. Furthermore, it often happens that the actual number of conductors which must be connected is not equal to the number of contacts in the commercially available connector which must be used so that, in effect, an oversized connector is used. The use of an oversized connector is undesirable, particularly if it is being used under circumstances where the space available is limited, for example in many electronic devices which are designed to be as compact as possible.

An object of the present invention is to provide an improved modular type multi-contact connector assembly which can be made to accept varying numbers of contacts and to connect varying numbers of conductors. A further object is to provide a modular type connector assembly comprising two connectors which can be engaged with and disengaged from each other with a low force requirement. A further object is to provide a modular type connector assembly having jack screw means for engaging the connectors with each other. A still further object is to provide a modular type connector which can be assembled from a relatively small number of component parts.

These and other objects of the invention are achieved in a preferred embodiment in which each connector comprises a plurality of connector modules secured together in side-by-side relationship. The user can thus assemble a connector of any desired size by merely assembling an appropriate number of modules to each other and securing them together by means of a clamping device. The modules of the preferred embodiment are hermaphrcditic; that is, two identical modules can be mated with each other so that only one basic type of module is required to assemble a connector. The modules are not rigidly mounted in side-by-side relationship but are mounted in a manner such that they are permitted a limited amount of float; that is, each module is permitted a limited amount of independent movement so that when two connectors in accordance with the invention are engaged with each other, each individual module in each connector is permitted to align itself with its counterpart with which it is to be engaged. Tln's feature of the invention avoids the need for a high degree 3,373,734 Patented Mar. 16, 1965 of dimensional precision such as would be required if the modules were rigidly mounted. A further feature of the preferred embodiment is that the contact terminals in the individual modules are recessed so that upon engagement of two modules with each other, the modules align themselves before the terminals are brought into engagement with each other. If desired, modular connectors in accordance with the invention can be provided with jack screw means for pulling the two connector parts into engagement with each other and holding them together, the preferred form of jack screw means also comprising a module which is mounted within the bank of connector modules.

In the drawing:

FIGURE 1 is a perspective view with parts broken away showing a preferred form of connector assembly in accordance with the invention.

FIGURES 2 and 3 are perspective views showing opposite sides of a connector module.

FIGURE 4 is a side view of the connector assembly of FIGURE 1 showing the two connectors disengaged from each other.

FIGURE 5 is a view taken along the lines S5 of FIGURE 4 showing specifically the jack screw means for the connector of FIGURE 1.

FIGURE 6 is a view taken along the lines 6-6 of FIGURE 4.

FIGURE '7 is a view taken along the lines 77 of FIGURE 6.

FIGURES 8 and 9 are views taken along the lines 8-8 and 99 of FIGURE 4.

FIGURES 10 and 11 are views taken along the lines Iii-Ill and III1 of FIGURE 8 and illustrating the clamping means of the preferred embodiment.

FIGURE 12 is a view on an enlarged scale taken along the lines 12-12 of FIGURE 9 and illustrating the manner in which the modules are mounted in the connectors.

FIGURE 13 is a perspective view of an end guide piece used in the embodiment of FIGURE 1.

FIGURE 14 a cross sectional view taken along the lines I4-I4 of FIGURE 17 but showing the modules in engagement with each other.

FIGURE 15 is a view taken along the lines I515 of FIGURE 14.

FIGURE 16 is a view similar to FIGURE 15 but showing contact terminals positioned in the module cavities.

FIGURE 17 is a side View of a pair of modules which are not in perfect alignment.

FIGURE 18 is a view similar to FIGURE 17 but showing the modules after initial engagement, these views being presented for the purpose of illustrating the self-aligning feature of the modules.

FIGURE 19 is a plan view showing a pair of modules which are misaligned in a plane extending normally of the plane of FIGURE 17.

FIGURE 20 is an exploded perspective view showing a modified form of connector assembly in accordance with the invention.

FIGURE 21 is a plan view of the connector of FIG- URE 20 showing the two parts of the connector in alignment with each other.

FIGURE 2.2 is an end view of the connector of FIG- URE 21.

FIGURE 23 is a view taken along the lines 2323 of FIGURE 22.

Referring first to FIGURES 1 and 4, a preferred form of modular multi-contact connector assembly in accordance with the invention comprises a connector 2 and a mating connector 4 which is secured to a panel 6. Both of these connectors are assembled from a plurality of identical modules generally indicated at 8 (FIGURES 2 and 3), which each contain four contact terminals which in turn are secured to the ends of conductors. The modules may be of any suitable insulating material such as relatively hard polycarbonate or nylon and may be formed by injection or other molding techniques. These modules are generally prismatic having rectangular-sides 10, 12, 14, 16. A notch 18 extends through each of the sides 14, 16, these notches each having a centrally located generally cylindrical rib 20 extending parallel to the module axis by means of which the modules are mounted in the connector as described below. Cavities (shown in FIG- URE 15 extend through the modulesfrom the rearward side 22 to the forward or mating end and are adapted to receive a type of electrical contact terminal disclosed in the copendingapplication of Lincoln Roberts, Serial No. 183,542, filed March 29,1962, for Electrical Connecting Device. It will be understood that this type or" contact terminal is shown by way of example only and that al ternative types of contacts, such as conventional pin and socket contacts, might be used.

Adjacent to the forward or mating end of each module, there is provided a forwardly facing shoulder 26 extending inwardly from, and normally of, the sides 12 and 16,. A pair of generally rectangular projections 28, 30 extend from this shoulder towards, but not up to, the forward end of the module, these projections constituting the walls or" two of the cavities of the module. The side 10 of the module extends toward the mating end of the module and forms a back wall 32 for the projections 28, 30. Sidewalls 34, extend from opposite sides of the projection 28, the sidewall 34 extending to the mating end of the module and the sidewall 35 terminating short of this end. A rib 37 is provided on the outside surface of the projection 28 and the wall 34 and extends to the end of the module. The adjacent sides of projections 28, 38 do not abut each other but a space 29 is provided between them which receives a complementary wall of a mating module as is described below.

An additional pair of cavity wall projections 38, 40 are provided on the opposite side of the module from the projections 28, 30. Projections 38, 40 are disposed in a recess formed by a wall 44, which is coplanar with and constitutes an extension of the side 12, and by an arm 36 on the side of the module. The projection 38 like the projection 30 is isolated from the projection 4i and from the arm 36 while the projection 41) has sidewalls 42 extending towards the mating end of the module but .termi nating short of this mating end. A slot 39 on the inside surface of arm 36 extends inwardly from the end of the arm for reception of the rib 37. The slot is advantageousin order to assist in aligning two misaligned modules as described below.

The design of the module is such that two identical modules can be engaged with each other by aligning them in opposed but inverted relationship with each other and pushing them together. As is apparent from FIGURE 14, when two modules are thus engaged with each other, the .end of the arm 35 of one module is disposed against the shoulder 26 and adjacent to the side 16 of the other module. The projection 38 of each module is received between the walls 34, 35 of the other module while the walls 42. of each module extend on each side of the projection 30 of the other module. It will thus be apparent that the modules can not be engaged with each other in any manner other than the proper and intended manner,

The curved surface 36 of each module in cooperation with sidewall 34 of the mating module corrects misalignment of the type shown in FIGURE 17 where the sides 14, 16 of the module pair are not initially aligned. The rib 37 of each module and the slot '39 of the mating module corrects misalignment of the type shown in FIGURE 19 where the sides 10 and 12 are out of alignment. If two modules are misaligned in a manner including both types of misalignment (FIGURE 17 and vFIGURE 19), both of the corrective effects will operate to align the module pair.

The initial or rough alignment of the modules will bring the sidewall 35 of each module in alignment with the gap between the projections 38, 40 of the other module and the sidewalls 42 in alignment with the projections 30 so that sidewalls 42 straddle the projections 30. Upon further movement of the modules into engagement with each other, the sidewalls 34, 35 will pass over and straddle the projection 38 and the sidewalls 42 will pass over and straddle the projection 35. During this second stage of alignment the two modules will align themselves in both planes as described above but to a more precise degree. This second stage of alignment is brought about by the rounded leading ends of the walls 35, 42 and by the rounded edges of these walls in cooperation with walls 32, 44 and the rounded leading ends of the projections 28, 30, as, as.

The two-stage alignment of the modules permits two modules to be brought into engagement easily and smoothly it they are relatively severely misaligned initially. Moreover, after full engagement, the modules will interfit relatively snugly sothat they will not move or wobble independently of each other and the contacts in the modules will thereby be held in engagement. This selfaligning ability of the individual modules permits the achievement of a modular connector assembly which has a low engaging force and which does not require precisely dimensioned parts as willbecome apparent as this description proceeds.

The contact terminals48 (FIGURE 16) as explained in the .copending Roberts et al. application, Serial No. 183,542, are of generally channel shaped cross section in their middle portions. Each contact has a relatively long contact arm 5t which projects'beyond a shorter contact arm 51. The arm 51 is disposed entirely within the cavity of the module after insertion while the long arm 58 projects beyond the cavity but terminates short 01" the ends of the sidewalls 34, 35, .42. Thus, when two modules having contacts therein are engaged with each other, the modules contact each other, move into partial engagement, and align themselves before there is any engagement between the contact terminals.

The modules 8 are arranged as a bank in the connectors 2, 4 in side-by-s ide relationship with guide bars 54 extending lengthwise along the exposed sides 14, 16 of the bank. These guide bars haxe X-shaped cross sections with one flange 56 being received within the notches 18 of the modules. Flange 56 of each guide bar has spacedapart semi-circular notches 58 (FIGURE 12) which con form to the radius of the semi-cylindrical ribs 29 in the notches 18 of the modules so that the ribs seat within the notches 56 and maintain the spacing between the modules. The spacing of the notches 58 on the guide bar is, in the preferred embodiment, greater than the thickness of the modules by an amount equal to the float or movement which is required to permit the modules to align themselves with their counterparts when the two .parts of the connector are engaged with each other. It will be apparent that the medial planes of the modules are spacedapart on theguide bar by an amount which is greater than the thickness of an individual module. Thus, in FIGURE 12 it'is apparent that a substantial spacing is rovided between the adjacent sides or" adjacent modules (this spacing 23 being exaggerated in FIGURE 12 in the interest of clarity).

The bank of modules is contained in the connectors 2, 4 between metallic guide blocks 70 (FIGURE 13) having a thickness substantially equal to that of the modules and having cars 71 extending from their opposite sides. Notches 73 extend through these cars and are provided with centrally located semi-cylindrical ribs (not shown) similar to the ribs 20 of the modules for positioning the guide blocks on the flanges 56 of the bars 54. A pair of fingers 72, 74 which are offset from each other, having rounded leading ends extend forwardly of the guide blocks and are so located that the blocks, like the modules are hermaphroditic. A recess '75 extends inwardly from the side of the guide block and a slot 69 at the bottom of the recess communicates with the rearward end of the block. This rearward end of the block has a shoulder 77 which is adapted to receive a generally channel shaped retainer 79 (shown in perspective in FIGURE 20). The retainer has an ear 81 projecting from one of its sides intermediate the ends from which a tab 83 is struck up so that the retainer can be fitted against the shoulder 77 with the tab or ear 81 extending into the slot 69 and the recess 75. The struck up tab 83 will prevent removal of the retainer and hold the parts, including the modules, together in a manner described below.

The connector 2 of the disclosed embodiment has a shield which is assembled from a pair of end pieces 60, 62 and a channel shaped cover 78. The end pieces are of generally rectangular shape and have bosses 64 in their lower corners, the bosses 64 of the end pieces 62 being threaded for the reception of the ends of rods 68. These rods extend the length of the connector on each side of the bank of modules and through openings in the bosses in the end pieces 60. Nuts 76 are threaded onto the ends of these rods to hold the end pieces 60, 62 to the bank of modules and the guide bars 54. The flanges 55 of the guide bars which are on the opposite sides from the flanges 56 are received within grooves 80 in the end pieces and in the cover 78. This cover is thus held between the end pieces and in surrounding relationshipto the conductors which extend from the modules. The web 82 of the cover has periodically spaced circular recesses 84 which permit the removal of a circular section for reception of a jack screw 94 described below.

The lefthand end piece 62 is provided with a cable clamp shown best in FIGURES 8 and 11. This clamp comprises a plate 1% slidably mounted in the end piece by means of guides 1l2 and having on its upper end an outwardly projecting flange K64 upon which there is a generally arcuate clamping surface 196. A flange 108 projects in the same direction as flange 104 from the upper end of the end plate and has complementary clamping surface 110 which is opposed to the surface 106. The plate 100 is drawn upwardly in FIGURE 8 by means of screws 112 threaded'through ears 114 on the flanges 1G4, and extending through the flange 108 so that upon turning of these screws the plate is pulled upwardly and into clamping engagement with a cable covering 116 (FIGURE 1).

If desired, a connector assembly in accordance with the invention may be provided with a jack screw for drawing the two connectors together. To this end, a jack screw module 86 is mounted in with the bank of modules in the connector 2. This jack screw module has grooves 88 on its opposite sides which have centrally located ribs similar to the ribs 20 to position the block 36 on the positioning bar 54. Module 86 has a central opening 90 which is provided with a metallic insert having a reduced diameter threaded central section. The jack screw 94 is inserted through an opening in the web of the shroud 78 formed by punching out one of the recesses 84 and is threaded through the threads in the central portion of the block until it projects beyond the face of the jack screw block. Thereafter a snap washer 98 is mounted on the reduced diameter end of the jack screw to prevent its withdrawal. A recess 99 surrounds opening 90 on the face of the module to permit seating of this snap ring when the modules are against each other. An identical module 86 is mounted in the bank of modules 8 in connector 4 so that the centrally located threads in the block 86 receive the threaded end of the jack screw in the conventional manner. Movement of the jack screw 94 through the module 86 is prevented by a shoulder which is of a diameter greater than the diameter of the central threaded portion of the insert 92.

In order to assemble the connector 2, the appropriate number of modules with a jack screw block in their midst and with guide blocks at their ends are positioned between a pair of guide bars 54 with each module having its positioning rib 20 disposed within a notch 58 in the bar. This assembly, including the modules, guide blocks, and jack screw blocks can then be held together by merely positioning channel shaped retainers 79 against the shoulders 77 of the guide blocks with the ears 81 extending into the slots in the guide blocks and with the tabs 83 locking the retainers in position. At this stage of the assembling operation, the two guide bars 54 will be clamped or held between the ears 71 of the guide blocks and the retaining clips 79 and the modules will be held on the guide bars between the opposed faces of the guide blocks 76. The ribs 20 of the modules and of the guide blocics will, of course, prevent their moving axially off of the guide bars. Thereafter, the end plate 62 is positioned over one end of the assembly with the wires extending through the opening in this end plate and the threaded rods 68 are threaded into the openings in the bosses 64 of end plates 62. End plate 60 is then positioned over the other end of the connector 2 and the nuts 76 are threaded onto the ends of these rods. The entire connector will then be completely assembled and the fasteners 112 can be drawn up to clamp the cable 116 for the wires. The jack screw can be inserted by merely threading it through the jack screw block 86 and positioning a snap washer 98 on its end.

The connector 4 is assembled in much the same manner as the connector 2, that is, the appropriate number of modules 8 are placed in side-by-side relationship against a positioning bar 54' with a jack screw module 86 disposed in the same relative location as the block 86 of the plug part 2. The guide blocks are then positioned at the ends of the bank of modules and the retainer clips 79' are inserted as before. The entire assembly is now com plete and can now be clamped to the panel 6 by means of generally C-shaped clamps 118 which are secured to the panel by fasteners and which have arms extending over the flanges 55 of the positioning bars 54'.

It will be noted in FIGURE 4 that the three modules on the left of each connector are oriented differently from the remaining modules of the banks. It is not necessary to arrange several modules in a reverse orientation for polarization since, as explained above, the modules themselves are self-polarizing and can not be engaged with each other unless they are properly aligned. However, the reversal of the three modules as shown has the advantage of visually indicating at a glance the proper orientation or polarization for the plug part 2 with respect to the receptacle part of the connector and additionally keys the connectors 2 and 4 to prevent their being engaged with other connectors.

The salient feature of the invention is that it permits the achievement of a modular connector assembly which can be made in any desired size capable of accepting contact terminals of the type requiring precise alignment when they are mated. Moreover, the parts from which the connector is assembled can be manufactured without the necessity of maintaining extremely close dimensional tolerances. This general feature of the invention is explained in detail in the following discussion.

Contact terminals quite often require fairly precise alignment with each other before they can be mated. The disclosed contact terminals (FIGURE 16), for example, could not be brought into engagement if they were offset from each other by a relatively slight amount. It

follows that a pair of connectors having cavities for the contacts must be constructed in a manner such that the cavities of the two connectors are in alignment when the modules ,3 in the instant invention, for example, can be controlled to within about $0.003" where the modules are about 0.175 in width and it is impractical to control this-thickness to a greater degree. The positioning bar 54 can not be made to precise dimensional specifications and the distance between the centers of the notches 58 can be heldonly to some fixeddimensions $0.003" with prac ticality. It follows that one of the connectors 2, 4 might be composed of modules 8 which are oversized relative to the nominal thickness by about 0.003 while the other connectormight have a predominant number of modules which are undersized by thesame amount. If the distances between the notches on the positioning bars also departs from the nominal dimension, it can be seen that ,exact alignment of theindividual pairs of modules would not be achieved and the contacts in the module cavities would not be aligned.

Inthe practice of the invention, however, misalignment of the modules, to the extent permitted by manufacturing variations of the modulesand the positioning bars, is not detrimental since the mating pairs of modules in the connectors 2, 4 will individually align themselves as pairs. The two-stage alignment of each pair, moreover, permits a substantial initial degree of initial module misalignment but results in close alignment of the contact terminals in the modules before engagement of the terminals. By way of contrast, if the modules 8 were snugly packed against each other in their banks, abuild-up or an accumulation of variations on the one connector with respect to the other connector would make mating of the two parts impossible;

A distinct advantage of the invention is that the connectors can be formed in any desired size. Thus, if an odd number of conductors must be disengageably connected with each other, sa 72 conductors, it is merely necessary to assemble a connector from 18 pairs of modules. A further advantage of the invention is that where a composite device or machine is assembled at one loca tion and its components are manufactured at diverse locations, the various electrical components can be wired, have contacts placed on the wire ends, and the contacts inserted into modules atthe time of manufacture. At the site of assembly of the composite machine, a connector can then be assembled with modules from different components which emanated from different ultimate sources.

FIGURES 20-23 show a modified form of the invention which does not have a jack screw but which rather provides a spring clip 122 for holding together the two parts of the connector assembly. In other respects, this embodiment is similar to the embodiment of FIGURE 1. Spring clip 122 has ears 126 which extend over the ears 71 of the guide blocks 79 and is secured to the guide blocks by means of fasteners 124 threaded into openings in the blocks. This clip has a divergent end 128. and a central inwardly directed detent portion 139 which is adapted to enter the recess 75' in the guide block of the mating connector. nector parts are merely pushed together until detent 13th enters the recess 75 and are held together by the resilient elfect of the clip. As with the previous embodiment, a C-shaped clamping member 118 may be provided to se cure one of the connector parts to a panel if desired.

Changes in construction will occur to those skilled in With this embodiment, the. two conthe art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective against the prior art.

I claim:

1. An insulating module having a plunality of cavities extending therethrough, contact terminals in said cavities, said module being matable with an identical module and having a mating end portion which interfits with said identical module, said module-having a first universal self aligning means -at the extreme end of said mating end portion, said first self aligning means comprising surfaces on said mating end which'are interengageable with complementary surfaces on said identical module within a relatively wide range of module misalignment, and a second self aligning means in said mating end portion recessed from said first self aligning means, said second self aligning means comprising surfaces which are interengageable with complementary surfaces on said identical module within a relatively narrow range of module misalignment, said contact terminals being recessed from said second selfs-aligning means whereby, said module can be mounted in a connector with said relatively Wide range of module misalignment and said contact terminals will be brought into alignment before coming into engagement with each other.

2. An insulating module having a plurality of cavities extending therethrough for reception of contact terminals, said module being matable with an identical module and having a mating end portion which interfits with said identical module, said module having a first universal aligning means at the end of said mating end portion, said first universal aligning means comprising a slot and a rib on opposite sides of said module for engagement with a slot and rib of said identical module, and said first aligning means comprising a curved surface on the end of said mating end portion extending obliquely of said rib and slot, and-a second universal aligning means in said mating end portion but spaced from the extreme end of said module, said second aligning means comprising walls and slots which interfit with said identical module, said walls and slots having curved engaging surfaces on smaller radii than said curved surfaces of said first aligning means whereby, upon movement of said module into engagement with said identical module, said modules are brought into alignment with each other in two'steps whereby said modules are snugly engaged with each other and said cavities of said modules are in alignment with cavities of said identical module.

3. 'An electrical connector comprising a pair of parallel spaced-apart rails having their corresponding ends connected to form a generally rectangular frame, a bank of side-by-side modules contained within said frame with said rails extending across the exposed sides of said modules, grooves in each of said exposed sides, said nails extending into said grooves, interenga-ging means on said rails and in said grooves for positioning the medial plane of each of said modules at a predetermined distance from the medial plane of the next adjacent module, said predetermined distance being greater than the thickness of an individual module by a given amount, and aligning means on the mating end of each of said modules, said aligning means comprising curved surfaces extending obliquely of the plane of each module and being capable of aligning a pair of modules which are misaligned by the amount permitted by the spacing between said interengaging means.

4. A device as set forth in claim 3 including a jack screw module in said bank .of modules, said jack screw -module having a threaded opening extending therethrough.

5. An electrical connector comprising a pair of parallel spaced-apart rails having their corresponding ends connected to form a generally rectangular frame, a bank of side-by-side modules contained within said frame with said rails extending across the exposed sides of said modules, grooves in each of said exposed sides, said rails extending into said grooves, interengaging means on said rails and in said grooves for positioning the medial plane of each of said modules at a predetermined distance from the medial plane of the next adjacent module, said predetermined distance being greater than the thickness of an individual module by a given amount said interengaging means permiting lateral movement of each of said modules within the limits of said predetermined distance, aligning means on the mating end of each of said modules, said aligning means comprising curved surfaces extending obliquely of the plane of each module and being capable of aligning a pair of modules which are misaligned by an amount equal to the spacing between said inter-engaging means on said rails, contact cavities extending through said modules and contact terminals in said cavities, said terminals being recessed from said mating end whereby, upon movement of said connector into engagement with a matin" connector, each of said modules aligns itself With its counterpart in said mating connector, and said contacts in each module are thereafter brought into engagement with contacts in said mating connector.

6. An electrical connector comprising a pair of parallel spaced-apart rails having their corresponding ends connected to form a generally rectangular frame, a bank of side-by-side modules contained within said frame, a plurality of cavities extending through each of said modules, contact terminals in said cavities, said rails extending across the exposed sides of said modules, grooves in each of said exposed sides, said rails extending into said grooves, intereng-aging means on said rails and in said grooves for positioning the medial plane of each of said modules at a predetermined distance from the medial plane of the next adjacent module, said predetermined distance being greater than the thickness of an individual module by given amount, a first universal self-aligning means on the mating end of each of said modules, said first selfaligning means compressing surfaces on said mating end which are interengageable with complementary surfaces on an identical module in a mating connector within a nange of module misalignment which is at least equal to the amount of misalignment permitted by the spacing between said interengaging means, :a second self-aligning means in said mating end portion recessed from said first self-aligning means, said second self-aligning means comprising surfaces which are interengageable with complementary surfiaces on said identical module within a relatively narrow range of module misalignment, said contact terminals being recessed from said second self-aligning means whereby, said module can be mounted in a connector with said relatively Wide range of module misalignment and said contact terminals will be brought into alignment with contact terminals in said mating connector before engagement.

References Cited in the file of this patent UNITED STATES PATENTS 1,183,516 Anderson May 16, 1916 2,945,201 Waninger July 12, 1960 2,964,724 Fox Dec. 13, 1960 2,984,814 Scott May 16, 1961 3,040,289 Wicks June 19, 1962 3,072,340 Dean Jan. 8, 1963 

1. AN INSULATING MODULE HAVING A PLURALITY OF CAVITIES EXTENDING THERETHROUGH, CONTACT TERMINALS IN SAID CAVITIES, SAID MODULE BEING MATABLE WITH AN IDENTICAL MODULE AND HAVING A MATING END PORTION WHICH INTERFITS WITH SAID IDENTICAL MODULE, SAID MODULE HAVING A FIRST UNIVERSAL SELF ALIGNING MEANS AT THE EXTREME END OF SAID MATING END PORTION, SAID FIRST SELF ALIGNING MEANS COMPRISING SURFACES ON SAID MATING END WHICH ARE INTERENGAGEABLE WITH COMPLEMENTARY SURFACES ON SAID IDENTICAL MODULE WITHIN A RELATIVELY WIDE RANGE OF MODULE MISALIGNMENT, AND A SECOND SELF ALIGNING MEANS IN SAID MATING END PORTION RECESSED FROM SAID FIRST SELF ALIGNING MEANS, SAID SECOND SELF ALIGNING MEANS COMPRISING SURFACES WHICH ARE INTERENGAGEABLE WITH COMPLEMENTARY SURFACES ON SAID IDENTICAL MODULE WITHIN A RELATIVELY NARROW RANGE OF MODULE MISALIGNMENT, SAID CONTACT TERMINALS BEING RECESSED FROM SAID SECOND SELF-ALIGNING MEANS WHEREBY, SAID MODULE CAN BE MOUNTED IN A CONNECTOR WITH SAID RELATIVELY WIDE RANGE 